• Sirikarn Khansumled

Student thesis: Phd


A range of poly(methacrylate/acrylate)-based uniform latexes with 0-5 wt% diacetone acrylamide (DAAM) and core:shell (70:30 and 80:20) latexes with 2-5 wt% DAAM in the shell copolymer were prepared by semi-batch emulsion polymerisation. All latexes were made with high instantaneous % conversions and approximately constant total particle number after the nucleation period. The particle morphology was confirmed by atomic force microscopy on cross-sections of latex films. All the copolymers have Tg values in the range -6 to -8 C. The keto-hydrazide crosslinking reactions were analysed to determine the loss of hydrazide molecules by high performance liquid chromatography. The uniform latex with no DAAM was found to give only a very slight reduction in the concentration of adipic acid dihydrazide (ADH) crosslinking agent, [ADH], showing that ADH does not diffuse significantly into the particles. All latexes and their aqueous phase extracts containing DAAM groups showed similar trends for substantial reduction of normalised [ADH] with time. Dried aqueous phase extracts from all latexes were analysed by gel permeation chromatography, which revealed two polymer components, one at higher molar mass and one at lower molar mass. These two components contained most of the DAAM groups, with the higher molar component most likely in the form of highly-swollen small particles and the lower molar mass component in the form of water-soluble copolymer chains. Only a small proportion of the DAAM groups are in the latex particles, most likely at the particle surfaces. The addition of ADH to the DAAM-containing latexes prior to film formation was found to have a significant effect on the stress-strain behaviour of films and, at stoichiometric levels 40%, led to a change from viscoelastic behaviour to strain hardening behaviour. The improvement in mechanical performance was shown to be due to the -C=N- crosslinks from the keto-hydrazide crosslinking reaction plus a small contribution from hydrogen bonding. Dialysed latexes show similar stress-strain behaviour to films from normal latexes, showing that the residual DAAM containing aqueous phase polymer (mostly highly-swollen particles) is sufficient to give rise to good mechanical performance.
Date of Award31 Dec 2017
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorPeter Lovell (Supervisor) & Robert Freer (Supervisor)


  • Water-borne polymers
  • Emulsion polymerisation
  • Keto-hydrazide Crosslinking
  • Diacetone acrylamide
  • Adipic acid dihydrazide

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